Editing Ground Units / Ground Combat

= Creating Ground Units / Ground Combat =

== Ground Forces: Unit Design ==

Ground Forces and Ground Combat are undergoing a huge expansion in C#. The VB6 Ground Unit becomes the Formation and the VB6 Ground Unit Type becomes the Formation Template. However, there are no longer any fixed unit types or unit values. Instead, there is endless scope for Formations and Formation Templates, based on a detailed design process at the Formation level and below. This will allow the simulation of ground forces from many science fiction genres. As this is a long topic, it is broken into several posts, each covering a different topic.

The most granular level is the '''Ground Unit Class''', which is an individual soldier or vehicle. One or more of the same Ground Unit Class are grouped into '''Formation Elements''', which in turn are grouped into '''Formations'''. Formations remain intact for movement purposes, but combat involves each individual unit (each soldier or vehicle). As individual units are now tracked for casualty purposes, readiness no longer exists. Morale is tracked at the Formation Element level (a group of the same unit class), so the infantry in a Formation may have different morale than the anti‑tank guns or artillery.

The design process starts with the Ground Unit Class. Two important factors in this design process are the '''Racial Armour Strength''' and '''Racial Weapon Strength''', shown at the top of the Ground Forces window.

Racial Armour Strength is based on the strength of the highest racial armour technology. Conventional Armour is 3, Duranium Armour is 5, etc. In the example screenshot, the Commonwealth has researched Ceramic Composite, which has a strength of 10.

Racial Weapon Strength is based on the highest tech level (TL) among Laser Focal Size, Railgun Type, Meson Focal Size, Particle Beam Strength and Carronade Calibre. For example, 15cm Laser Focal Size is TL3 as it is the third tech of that type. Racial Weapon Strength is the value of armour at the same tech level. In this case, the Commonwealth has researched 20cm Laser Focal Size, which is TL4. The fourth Armour Tech is Ceramic Composite, which has a strength of 10, so the Racial Weapon Strength is 10. Armour is used as the basis for Weapon Strength so that Ground Armour and Ground Weaponry remain aligned and because it provides a straightforward way to assign value across very different weapons.

=== Base Types ===

The Ground Unit Design tab of the new Ground Forces window begins with selecting a '''base type''': infantry, several sizes of vehicle, or static. Static units are weapons that are not self‑mobile, such as towed anti‑tank guns or towed artillery. Static weapons remain in place when firing, so they are easier to hit than infantry or vehicles.

Each base type has six main characteristics:

; Size (tons)
: Size determines transport requirements and cost, although other modifiers also affect cost.

; Hit Points
: Unit hit points are compared to weapon damage during combat to determine the chance of destruction (the Damage Check).  
: Chance to destroy = (Weapon Damage / Hit Points)^2

; Slots
: The number of component slots available for the base type.

; To‑Hit Modifier
: Modifies the chance of the unit being hit during combat (based on mobility). Applies only if the unit is not fortified.

; Maximum Fortification
: Maximum strength to which the unit can be fortified by construction factories or construction units.  
: Chance to Hit is divided by the fortification level.

; Maximum Self‑Fortification
: Maximum strength to which the unit can be fortified without construction factories or construction units.

=== Armour Types ===

The Armour of a unit is compared to the Armour‑Penetration (AP) value of a weapon.  
Chance to penetrate = (AP / Armour)^2

For example, AP 4 vs Armour 6 → 45% chance to penetrate.

The overall destruction process is:
# Chance To‑Hit  
# Armour Penetration Check  
# Damage Check  
All three must succeed to destroy the target.

Each Armour Type has two values:

; Base AR
: Base Armour Rating × Unit Size determines cost.  
: A unit with AR 6 costs 50% more than the same unit with AR 4.

; Racial AR
: Base Armour Rating × Racial Armour Strength.

=== Components ===

Below the base type and armour is the Components section.

* Infantry, static, and light vehicles have one component slot.
* Vehicles and heavy vehicles have two slots.
* Super‑heavy vehicles have three slots.
* Ultra‑heavy vehicles have four slots.

Each slot can hold one component from the list, and the same component may be used multiple times. Some components are restricted to certain base types (e.g., Super‑Heavy Anti‑Vehicle components require super‑heavy or ultra‑heavy vehicles).

Each component has a name, abbreviation, and nine ratings:

; Size
: Added to the size of the base unit type.

; Armour‑Penetration (AP)
: If the component is a weapon, chance to penetrate = (AP / Armour)^2.  
: AP Rating = underlying AP × Racial Weapon Strength.

; Damage
: If the component is a weapon, chance to destroy after penetration = (Weapon Damage / Hit Points)^2.  
: Damage = underlying damage × Racial Weapon Strength.

; Shots
: Number of times the weapon fires per ground combat phase.

; CIWS
: '''Y''' indicates a Close‑In Weapon System capable of defending the planet from missile attack.

; STO
: '''Y''' indicates a Surface‑To‑Orbit energy weapon capable of engaging ships in space.

; HQ
: Headquarters capacity in tons. Determines the total formation size that can be commanded.

; FFD
: '''Y''' indicates Forward Fire Direction. Allows a front‑line unit to direct supporting bombardment units, fighters on close air support, or ships in orbit.

; Const.
: Construction value in Construction Factory Equivalents (CFEs).

=== Capabilities ===

The Capability section (top‑right of the window) allows selecting one or more capabilities for the Unit Class.

* '''Boarding Combat''' is required for boarding ships.
* All other capabilities…

== Ground Forces: Formation Templates ==

The Formation Templates tab of the Ground Forces window is the equivalent of VB6 Ground Unit Types, although it may be easier to think of them as serving the same function as Ship Classes. A Formation Template is a detailed design that serves as the blueprint for building Formations based on that design, in the same way Ship Classes define Ships.

This tab is split into two halves. On the left is a list of available Ground Unit Classes created using the Unit Class Design tab (explained in the previous rules post). All of these were created using TL4 technology, with three exceptions. For comparison purposes, the Challenger 2 Main Battle Tank and the Warrior AFV were created using Conventional rather than Trans‑Newtonian technology, while the “Challenger – Base TN Upgrade” was the Challenger design with TL1 technology.

=== Formation Templates ===

The right‑hand half of the tab shows Formation Templates. A new Formation Template is created by clicking the '''New''' button. In this example, four templates already exist. Each Template consists of one or more Template Elements, shown in the bottom‑right section.

For example, the '''Guard Armoured Regiment''' has four template elements:
* 60× Leman Russ Battle Tank
* 1× Macharius Command Tank
* 12× Hydra Flak Tank
* 24× Hellhound Anti‑Infantry Tank

Each Template Element has the following attributes:

; Name
: The Unit Class for this element.

; Units
: Number of units of that Unit Class in this element.

; Size
: Total size in tons.

; Cost
: Total cost in Build Points.

; HP
: Total aggregate Hit Points.

; HQ
: Headquarters capacity of the Unit Class.

; FFD
: Total number of Forward Fire Direction components.

; Const.
: Construction value in CFEs.

; CIWS
: Number of CIWS components.

; STO
: Number of STO components.

=== Editing Templates ===

To add new Template Elements to a Formation Template, use the '''Add Units''' button with the adjacent text field. The number can be edited later using the '''Edit Amount''' button. Both Formation Templates and Template Elements can be deleted using the appropriate buttons.

=== Example: Brigade Headquarters ===

This screenshot shows the Macharius Command Tank on the left and the Brigade Headquarters formation template on the right.

The Macharius is a super‑heavy vehicle with:
* two super‑heavy anti‑vehicle weapons
* an HQ4 component (10,000‑ton HQ capacity)
* a size of 518 tons
* a cost of 93.24 BP

The Brigade Headquarters formation template includes:
* 2× Guard Brigade Headquarters units
* 36× large artillery pieces
* 12× flak tanks
* 1× company of Guardsmen

== Base Ground Combat Rules ==

Ground combat is conducted after the naval combat phase of each increment. One combat round will be performed for every eight hours that passed in the increment. Combat potentially takes place on any system body where populations exist from two or more hostile powers. If only one side has ground forces present, there may be a conquest (rules and code TBD). If ground forces are present from two or more hostile powers, ground combat will take place.

Ground forces can be assigned one of four field positions: '''Front Line Attack''', '''Front Line Defence''', '''Support''', and '''Rear Echelon'''. Units in Support and Rear Echelon positions cannot directly attack hostile forces, but if they possess elements with bombardment weapons they may be assigned to support a front line formation. Support and Rear Echelon formations can also potentially provide anti-air cover and supply to front line units. Only formations with all elements supplied can be placed in Front Line Attack mode. Formations placed in Front Line Attack mode lose any fortification bonus.

[[File:Bombardment Unit Range.png]]

Each race involved in a combat on a system body creates a list of its own formations on that system body (even if in multiple populations), plus a list of hostile alien formations, even if they are from multiple alien races in multiple populations. Hostile formations are checked for their weighted size. This is based on actual size for front line, 25% for support, and 5% for rear echelon. Each hostile formation is given a range for potential selection based on its weighted size.

Each front line friendly formation randomly targets a hostile formation. Friendly units with Front Line Defence can target hostile front line formations. Friendly units with Front Line Attack can target any hostile formation, although Support and Rear Echelon are less likely given their smaller weighted size. The more formations that are pushed into front line positions, the less likely it is that rear areas will be attacked.

Support and Rear Echelon formations that contain formation elements with bombardment weapons can be assigned to support front line formations that are part of the same organisation. Formations in a Support position with light bombardment weapons will fire with the front line formations. Formations in a Support position with medium/heavy bombardment weapons, or formations in a Rear Echelon position with heavy bombardment weapons, will fire in a subsequent phase.

Once a front line formation (or a light bombardment element in Support) has been matched against a hostile formation, each friendly individual unit (a soldier or vehicle) in that formation engages a random element in the hostile formation, with randomisation based on the relative size of the hostile formation elements. This represents combined-arms cooperation (infantry supporting tanks, etc.).

Once all front line attacks have been concluded, each unit in each element providing supporting bombardment will engage either:
* the hostile formation being targeted by the friendly formation they are supporting, or
* one of the hostile formation’s own supporting elements (counter-battery fire).

If the hostile formation is targeted, each unit in the supporting artillery element engages a random element in the hostile formation. If a hostile supporting element is targeted, all fire is directed against that element.

Supporting medium artillery will choose between hostile forces in Front Line or Support positions (ignoring Rear Echelon). Heavy artillery can select targets in any field position.

Once all initial combat is complete, there is a chance for a breakthrough. Each defending formation is checked:

=== Breakthrough Procedure ===

; Cohesion Damage
: For each formation element:
: '''Cohesion Damage''' = (Element Class Size) × (Units Destroyed in Combat Phase) × (100 / Element Morale)

The total Cohesion Damage is summed for all elements and compared to the formation size. This value (0–100%) is the '''Formation Cohesion Rating'''.

; Breakthrough Value
For each front line formation that attacked the defender:

* Static elements have zero Breakthrough Value.
* Vehicle elements:
: (Element Class Size) × (Element Units) × (Element Morale / 100)
* Infantry elements:
: Same formula × 0.5

The total Breakthrough Value is summed and compared to formation size. If the formation is in Front Line Attack, multiply by 2. This value (0–200%) is the '''Formation Breakthrough Rating'''.

; Breakthrough Potential
'''Breakthrough Potential''' = (Defending Cohesion Rating) × (Attacking Breakthrough Rating)

If ≥ 30%, a breakthrough occurs.

Each formation that creates a breakthrough mounts a second attack. This attack:
* does not benefit from supporting artillery or fighter support
* functions as if the formation is in Front Line Attack
* may target any hostile formation

Breakthroughs are more likely when:
* multiple attackers strike one defender
* the defender suffers high casualties
* casualties fall on large-class elements
* defender morale is low
* attacker is vehicle-heavy
* attacker is in Front Line Attack
* attacker morale is high

=== Combat Resolution ===

When a formation element engages a hostile element, supply is checked. If supply is unavailable, only 25% of units fire.

For each attacking unit:

; To Hit Chance
: Base chance = 20% × (Dominant Terrain To Hit Modifier) × (Element Morale / 100) × (Base To Hit for target unit class if target is not fortified)

; Fortification Modifier
: Target Fortification Level × (Dominant Terrain Fortification Modifier).  
: If target is not fortified, this modifier = 1.

; Environment Modifier
: Based on gravity, pressure, temperature, and element capabilities.  
: Each untrained environment doubles the modifier.

; Terrain Capability Modifier
: If trained for dominant terrain, modifier = 0.5.

; Final Chance to Hit
: '''Final Chance to Hit''' = To Hit Chance / (Fortification Modifier × Environment Modifier × Terrain Capability Modifier)

The unit fires each weapon it has (except non-bombardment weapons for units bombarding from Support or Rear Echelon). If the to-hit roll ≤ Final Chance to Hit, the weapon hits.

; Armour Penetration
: If AP ≥ Armour → penetration  
: If AP < Armour → chance to penetrate = (AP / Armour)^2

; Damage
: If penetration occurs → chance to destroy target = (Weapon Damage / Target Hit Points)^2

If a target is destroyed:
* the firing element gains morale
* the target element loses morale
* morale gain/loss is doubled in Front Line Attack mode

All combat is simultaneous and losses are applied after all firing is complete. Multi-way conflicts with multiple races on each side are possible.